Like all of you minecrafters will have noticed by now, beta 1.4 was released 2 days ago.
There have been quite some features added, but the best one by far, is that they added wolfs!
... or dogs, I'm not quite sure yet.
The wolves just wander about a little, and you can turn them into a dog by giving them 2 bones. Which will make them tame, and they'll follow you around, helping you fighting zombies (not creepers though, appartenly even wolfes/dogs are afraid of green penises (something which I can relate to)) The best thing about them though, is that they do not despawn, which is great, because this means you can enjoy the company of your wolf/dog everyday.
Here's a little video of the wolfdog in action
See, this video calls them Dogs. I think they're more like catdog. Except the other part is a wolf, which makes them Wolfdogs. Or dogwolfs ofcourse, whichever you prefer